Self-sealing wrapping material



Nov. 7, 1950 B. TRILLlcH sELF-sEALING WRAPPING MATERIAL 2 Sheets-Sheet 1Filed Nov. 7, 1949 Nov. 7, 1950 B. L. TRM LlcH SELF-SEALING WRAPPINGMATERIAL 2 sheets-sheet 2 I Filed NOV. 7, 1949 co//fs/vf conf/MgPatented Nov. 7, 1950 asista SELF-SEALING WRAPPING MATERIAL BertramrL.Trillich, Winnetka, Ill., assigner to The Munising Paper Company,Chicago,"lll., a

corporation of Ohio Application November 7, 1949, Serial No. 125,973

9 Claims.

This invention relates to a wrapping material especially adapted forwrapping small articles and more particularly to a quick-sealing,moisture-proof,A wrapping paper for wrapping a comestible to maintainits moisture content. In its preferred aspects, the invention relates toa quick-sealing, mosture-vapor-proof wrapping paper.

This application is a continuation-impart of my copending application,Serial No. 659,278, led April 3, 1946, now abandoned.

The `wrapping material of the present invention consists of a paper-thinflexible carrier sheet, preferably of paper, having a iiexible coatingof a moisture-proof material, preferably a moisturevapor-proof material,on one side thereof and on the other side a flexible coating or film ofa self-adhering material which is'substantially dry to the touch andsubstantially non-tacky but which is cohesive even under light pressure,and yet which is for' all practical purposes non-adhesive to any surfacesuch as paper, Cellophane, wood, glass, metal, paint, rubber, etc.,devoid of said material. The self-adhering materials which may be usedin accordance with the present invention are known materials and areusually termed cohesive, substantially non-adhesive materials. Forconvenience, these materials will be similarly referred to herein. Anysuch self-adhering materials may be used in accordance with the presentinvention.

The combination of a flexible water-proof coating on one side of aexible carrier sheet and of a cohesive, substantially non-adhesivecoating or film on the other provides a wrapping material for foodstuffshaving desired moisture-proof or moisture-vapor-proof properties and aversatilityl and ease of use not heretofore present in any of the priorart wrapping materials, insofar as Iam aware. The wrapping material ofthe present invention 'may be manipulated readily in sealingrelationship about foodstuffs or dishes or other articles containing thesame without the aid of heat or other extraneous expedients which entailskill and are inconvenient for the user.

In its preferred aspects the wrapping material of the present inventionconsists of ayflexible, calendered paper sheet, one surface of which iscoated with a flexible nlm or coating of a wax and the other with a iilmor coating of a cohesive, substantially non-adhesive rubber such as thefilm or coating of coalesced rubber particles deposited from a driedcoating of unvulcanized natural rubber latex. hesive,substantially.non-adhesive materials may 2 be used as the self-adherent coatingfor'the wrapping paper of the present invention, such as unvulcanizedBuna S latex, the latics'of other unvulcanized synthetic rubbers, andtheplasticized polyvinyl acetate compositions disclosed in Patent No.2,371,001, granted March 6, '1945, or y any mixture of such materialsincluding 'natural rubber, the coating of unvulcanized natural rub'- berdeposited from a latex of the same' is preferred because Ysuch a coatingcooperates "uniformly effectively with the wax lm'in imparting theproperty' of moisture-'proofness or moisturevapor-proofness to th'epaper sheet.

Any paper-thin, flexible' carrier' sheet which lends itself for use inwrapping small articles may be used iny accordance with my invention,although paper is preferred as' noted above. With such sheets, therubber (natural arid/or synthetic) or other cohesive,substantiallygnon-adhesive material cooperates with the'waxto seal any'imperfections in the sheet and/or'toimpart the desired moisture-prooformoisture-vaporproof 'properties to the sheet. When 'paper'is used asthe carrier sheet it is preferred `that it be'a lightly `sized paperwhich permits some surface penetration of latex (natural or syntheticrubber) .n Othei` papers such as hard sized' papers may, of course, beused. With such hardsized papers it may be necessary to overcome theeifect of this sizing by the .addition to the latex ofya surface activeagent to reducethe surface tensinV of the latex and to increase thewetting and penetrating power thereof.' Any suitable surface ac'- tiveagent may be used for this purpose'. EX'- amples of suitable surfaceactive' 'agents `are I sodium lauryl sulphate, sodium cetylsulphata'thesodium salt of the dioctyl ester of sulfo'succinic herently has` thedesired cohesive, substantially non-adhesive properties.

.Desired cohesive, substantially non-adhesive properties of a iilmvdeposited VfromY a latex'of unpaste or a water-soluble casein paste, andabout 2% tol5% by volume of glycerine.

As pointed out above, any cohesive, substantially non-adhesive materialmay be used in accordance with the present invention. Thus, suchmaterials may be made or compounded in accordance with known proceduresfrom aqueous dispersions or latices of diolen polymers other thannatural rubber, such as gutta percha, balata, polyisoprenes and thelike;` or from synthetic` rubbers s uch as butadiene polymers, forexample, buna rubber, butylene polymers such Yas polyisobutylene(Vistanex) and butadiene copolymers lsuch as the co-polymers ofbutadiene and styrene (Buna VS, Hycar OS,V etc.) and butadiene andacrylonitrile (Buna N, iHycar OR, Thiokol RD, etc); Buna S and Buna Ncold rubbers which are'obtained by copolymerization at temperaturesbelow normal room temperatures and preferably at temperatures of about41 F. and below; chloroprenes such as chloro- A typical Cil prene aloneor co-polymerized with acrylonitrile,

etc. (Neoprene) (zo-polymers of oleiins and diolens such as isobutyleneand butadiene or isoprene (Sutyl rubber); organic polysuld'es such asethylene polysulde formed by reacting ethylene dichloride and sodiumtetrasulde (Thiokol A); the reaction product of ,dichloroethyl ether andsodiumV tetrasulde (Thiokol Bor Perduren G) and rubbers derived fromunsaturated long-chain acids from soybean and other oils polymerized andthen esteried with a glycol such as ethylene glycol (Norepol, Agripol).

Other synthetic rubber latices may be used to make the cohesive,substantially non-adhesive materials used in accordance with myinvention and these may be any latex selected from the class prepared bythe polymerization in aqueous emulsion of a butadiene-1.3 hydrocarbonsuch as butadiene-1,3, isoprene. 2,3-dimethvl butadiene- 1.3, piperyleneor the like either alone or in admixture with each other and/or inadmixture withlesser or equal amounts of one or more monoethyleniccompounds copolymerizabletherewith in aqueous emulsion such asacrvlonitrile. methacrylonitrile. alpha-chloro acrylonitrile and similaracrylic nitriles; styrene. vinyl naphthalene, p-cbloro-styrene andsimilar aryl olefine and substituted aryl olens: methyl acrylate, methylmethacrylate. acrvlamide and similar esters and amides of acrylic acids;methyl isopropenyl ketone, vinylidene chloride, isobutylene,rnethylvinyl ether, and other compounds containing a single ethylenicdouble bond, C=C which are copolymerizable with butadiene-1,3hydrocarbons in aqueous emulsion. compounds which may be termedbutalastics as defined in the book Butalastic Polymers, a'Treatise onSynthetic Rubbers by Marchionna may be used.

The cohesive, substantially non-adhesive materials may be formed fromsynthetic resins other than those described in the abovev noted PatentIn fact, any of the No. 2,371,001. Thus they may be formed fromco-polymers of polyvinyl acetate and polyvinyl chloride, polyvinylacrylate, polyvinyl methacrylate, polyvinyl ethacrylate and likeacrylates having from 1 to 5 carbon atoms in the alkyl group, polyvinylethers, polyvinyl ketones such as methyl vinyl ketone, polyvinylalcohol, polyvinyl acetals such as form-al, butyral, etc., and the like.

As is manifest from the foregoing, any rubber, synthetic rubber andsynthetic resin, or any mixture thereof, may be used in forming thecohesive, substantially non-adhesive materials used inaccordance withthe present invention. In general the rubbers and resins are used inaqueous dispersion (latex) form. The amount of c0- hesivejmaterialapplied to the carrier sheet may be varied widelyQsay from about 0.2 lb.to 2 lbs. (solids) per 144 sq. yds. of carrier sheet.

The following are examples of cohesive, substantially non-adhesivematerials including such latice-s. l

Parts by weight 1. Natural rubber latex 100.0

Dibetanaphthyl p-phenylene diamine (antioxidant) 1.0 2.Butadiene-styrene copolymer 100.

VSodium silicate 0.5 Antioxidant as in Example 1 1.0 Ester gum 1.0 3.Butadiene-acrylonitrile 100.0 Soldium silicate 0.5 Antioxidant as inExample 1 1.0 Ester gum 1.0 4. Polyvinyl acrylate latex 100.00

Antioxidant as in Example 1 1.0 5. Chloroprene 100.0 Sodium cetylsulphate 0.5 Antioxidant as in Example 1 1.0 Zinc oxide 5.0 Ester gum1.0

Any suitable wax or wax-like material such as paraffin wax, beeswax,montan wax, carnauba wax, synthetic waxes such asrtheV high meltingpoint synthetic wax sold by Glyco Products Co., Inc., under thetrade-mark Acrawax C, and the like may be used :as the moisture-proofcoating for Vthe wrapping material of the: present invention. Thiscoating may be applied to the carrier sheet in any desirable manner, inaqueous emulsion form from solvent solution, or from molten bath, forexample, as is lwell understood. Other suitable moisture-proof materialssuch as the known lplastic compositions of wax and Vrubber Amay also beused, as may valso the relatively high melting point microcrystallinewaxes.

When such waxes are combined with the cohesive, sub'- stantiallynon-adhesive materials on opposite sides of a paper carrier sheet, thecarrier'sheet is rendered moisture-vaporproof- As is known,

vsuch waxes consistA of amorphous, substantially saturated compoundsthat have been formed from high boiling point, non-saturated petroleumderivatives by way. of polymerization and possibly by condensation(which products in the raw state 'areV known commercially as petrolatum)and, more speciiically, those higher melting point substances separatedtherefrom and sold as petroleum wax. Thesemicrocrystalline waxes Vmay beused alone or they may be ad- Y.

mixed with a material such'as 4coumarone resin, phenol-formaldehyderesin, cop-al gum andthe like, which will form a colloidal suspension orgel with the microcrys'talline wax, to increase scribed inthe DreymannPatentfNo. 2,031,036.

The presentinvention Will-be fully understood from the foregoing andfrom lthe `following dethereof taken along the line 2-'-2 of'rFig; -l;

Fig. 3 illustrates'the use of the coated paper of Fig. 1 for wrapping asandWich,-the 4latterbeing shown as resting 'on'the cohesive'surfaceoithe paper;

Fig. 4 is a cross-sectional view of the Wrapped sandwich takensubstantially along fthe `line ll-fl of Fig. 3;

,Fig 5 Yis a similar crossesectional view taken:-

substantially along the line 5-5-0f" Fig. 4;

Fig. 6 illustrates the use' ofthe paper oi-'Fig 1 for wrappingfoodstuflswhich are con-tained in an articlesuch as a dish;

Fig. 7 depicts thepaclrage yformed Vby wrap` ping the paper about vthe'foodstuffs4 in the dish in accordance withfthe present-invention; and*Figs S and 9 illustrate Inodiedembodiments oifthel coated sheets of thepresent invention.

In the drawings the'numeral "ldesignates a--fleXible paper'sheet;Vpreferably a lightly sized paper sheet which permits of somesurfacepenetration of a latex, the numeral il designates a Wax or otherWater-prootormoisturewaporproof coating, andthe numeral'IZdesignates'the cohesive, `substantially l nonadhesive coating,preferably of- -natural'rubber latex and preferably app-lied uniformlyand lightlyv'over the surface of the paper. vAs pointed out above,the-preierred cohesive, substantially nonad-hesive coating is formedbydryin/g an unvulcanized natural latex upon the surface of a'sheet ofpaper.'v The solids content of -this or any other latex 'which may beused iii-accordance with the presenti-m vvention maybe/varied widely, asdesired, from about 10% to about 50% to 60%. "For most purposes about a'35 solids content latex. is suitable.

In the use of 'this coated paperuto wrap comestiblesI-for example,a'sandwich, tthe sandwich, indicated by the numeral l5, is--placeduponthe cohesive coating fof Athe-paper `sheet vadj acent one end and withinthe boundaries thereof; as illustratedin'Fig; 3. Thefother end-of thecoated sheet is then'olded over'the sandwich so-that marginal portionsoi theY cohesive coating ofthe folded sheet are iny opposedrelationship. v A light pressure is' then applied-tothe opposedsurfacesof the cohesive coating by running'the' i^ingers lightlyaroundithemarginal portions of the lfolded paper, thereby completelysealing the sandwich within a ymoisture--prooipaclragaillustratedinFigs. l and 5.

In the use oi thepaper of the present-invention to wrap foodstuffcontained within a' dish or other article, the article containing-the1ioodstuif, indicated by' the numeral il, is placed upon the cohesivecoating of thepaper, as shown in f Fig. 6, and the free ends of the*paper are pulled up around the foodstuffand bunched'together with thecohesive coating surfaces in opposing relationship, therebyenclosingtheffoodstu in a water-proofl package whichmay bep-laced in arefrigerator untilready for use.

* Due to `the vlmoisture-proof or moisture-vapor-Y z:proofcharacteristics of lthe :Wrapping sheetgof .therpresentinvention-,afoodstuis Wrappedwithin this sheet-may be .keptwithin a`refrigerator for substantial periods .of-time, without, desiccation for decay..and.without.acquiring the-'i'lavors of otherv foodstuffs. Thecontents ofgthe package maybe readily removedueitherrby ycutting thewrapper or by. pulling it apartyatthe joining surfaces. In the. lattercase, if care is exercisedin pulling the 'surfaces apart, the` sheetVmaybe re-used.

lThe coated paper sheet referred to above has the-cohesive;-substantially non-adhesive coating all over one-surface thereof and thewax over the other-surface and these'sheets may be stacked one upon theother without adherence, by placing the cohesive coating of one sheet incontact with Vthe Wax coating ofY another.

The versatilityfof the coated sheet to ywrap various articles may ybeincreased by applying additional zonesof Vthe cohesive, substantiallynon-adhesive coating on the side of the sheet containinglthe wax orother Water-proof coating, l asillustrated in Figs. 8 and 9. In makingthese sheets the paper or other carrier sheet is coated on one sidethroughout the area thereof with a cohesive, substantially non-adhesivecoating as before anda similar coatingfis' applied to the side. Thewaxis then .appliedtothe-carrier-sheet between the areas delineated bythezones of cohesive, substantially non-adhesive coating.

"InFig 9,'the cohesive, substantiallyfnon-adhesive coating l 8 is.applied all over the surface of one side of vthe, carrier sheet and,additionally, f alongthe longitudinal margins I9 lon the opposite sides.The wax coating, 25 is a'ppliedfto the carrier sheet overthe areabetweenthe zones of cohesive, substantially non-adhesive coating. In theembodimentl of the invention illustrated in Fig. 8, vthere areadditional .zones 1 of cohesive, Vsubstantially non-adhesivecoatingZlwhich eX- tend between thel marginal zones i9 of cohesive,substantiallyV nonadhesive coating,A at.- intervals throughoutthe-length of the sheet.

For convenience of the. user any of'thecoated sheets describedabove'mayrbewvcnded in the form of a roll',.illustratedin Fig. 8, andtransverse perforations of score lines, illustrated by the score lines'22, may :be provided to enable the user to tear a piece ofthis Wrappingsheet from the roll. Wherethe fwrappingsheet of the present invention isprovided with .cohesivesubstantially non-adhesive `coatings onboth'sides, as in Figs. 8

polymers of butadienewith styrene and acrylonitrils; etc., as pointedout above.

f I- claim:

1, As a. new article of manufacture, a" sheet of self-sealing nwrapping' paper comprising a flexible paperzfbase having a1;cohesive,substantially dry,` non-.adhesive andnon-tacky wax-,tree

' coating consisting essentially,ofigunvulcanized natural rubber on theentire area of one side thereof and marginal Zones of a similar coatingon its other side, said other side of the paper base having an exposedcomparatively thin flexible lm of wax over the area between said zones,said coatings being exposed and adapted, when portions thereof arebrought into engagement with one another by slight pressure during aWrapping operation, to have such portions adhere to one another bycohesion, and serving to assist the Wax film in rendering the sheetmoisture-proof.

2. As a new article of manufacture, a sheet of self-sealing wrappingpaper comprising a thin exible calendered paper base having a cohesive,

substantially dry, non-adhesive and non-tacky,

wax-free coating consisting essentially of unvulcanized natural rubberon the entire area of one side thereof and Zones of a similar coating onits other side, said other side of the paper base having an exposediiexible film of wax over the area between said zones, said coatingsbeing exposed and adapted, when portions thereof are brought intoengagement with one another by slight pressure during a wrappingoperation, to have such portions adhere to one another by cohesion,andserving to assist the wax film in rendering the sheet moisture-proof.

3. As a new article of manufacture, a sheet of self-sealing wrappingmaterial comprising a thin brous lrn base having on the entire area ofone side thereof only an exposed comparatively thin flexible wax coatingfor purposes of moistureproofing the sheet and on the entire area of itsother side an exposed wax-free coating consisting essentially ofunvulcanized natural rubber deposited from an aqueous latex dispersioncontaining a small amount of material selected from the group consistingof starches and caseins, said last mentioned coating being cohesive,substantially dry, non-adhesive and non-tacky and adapted, when portionsthereof are brought into engagement with one another by slight pressureduring a wrapping operation to have such portions adhere to each otherby cohesion, and serving to assist the wax coating in rendering thesheet moisture-proof.

4. As a new article of manufacture, a sheet of self-sealing wrappingpaper comprising a thin flexible paper base having on the entire area ofone side thereof only an exposed comparatively thin flexible wax coatingfor purposes of moisture-proong the sheet and on the entire area of itsother side an exposed wax-free coating consisting essentially ofunvulcanized natural rubber deposited from an aqueous latex dispersioncontaining a small amount of material selected from the group consistingof starches and caseins, and in addition a hydroscopic substance, saidlast mentioned coating being cohesive, substantially dry, non-adhesiveand non-tacky and adapted to stick only to itself and, when portionsthereof are brought into engagement with one another by slight pressureduring a wrapping operation to have such portions adhere to each otherby cohesion, and serving to assist the wax coating in rendering thesheet moisture-proof. y

5. As a new article of manufacture, a moistureproof sheet ofself-sealing wrapping material adapted completely to encase an articleand thereby seal the same against outside moisture, said articlecomprising a thin flexible paper sheet normally pervious to moisture,said sheet having on one surface thereof an exposed comparatively thinexible wax lm coating completely covering said surface and therebyYimparting moistureproof properties thereto and on its other surface anexposed flexible dried wax-free lm consisting essentially of coalescedunvulcanized natural rubber particles, said film covering the completesaid other surface of the sheet and being substantially dry andnon-tacky and yieldingly self adhering when portions thereof are broughtinto engagement, but being non-adhesive to such surfaces as wood, glassand metal, the said non-tacky self-adhering nlm cooperating with saidwax coating in moisture-proofing said paper sheet.

6. As a new article of manufacture, a moistureproof sheet ofself-sealing wrapping material adapted completely to encase an articleand thereby seal the same against outside moisture, said articlecomprising a thin flexible paper sheet normally pervious to moisture,said sheet having on one surface thereof an exposed comparatively thinflexible wax film coating completely covering said surface and therebyimparting moistureproof properties thereto and on its other surface anexposed flexible dried wax-free film consisting essentially of coalescedunvulcanized rubber particles, said last mentioned lm covering thecomplete said other surface of the sheet and being substantially dry andnon-tacky and yieldingly self-adhering when portions thereof are broughtinto engagement, but being non-adhesive to such surfaces as wood, glassand metal, the said non-tacky self-adhering lm cooperating with said waxcoating in moisture-proofing said paper sheet.

'7. As a new article of manufacture, a moistureproof sheet ofself-sealing wrapping material adapted completely to encase an articleand thereby seal the Same against outside moisture, said articlecomprising a thin flexible paper sheet normally pervious to moisture,said sheet having on one surface thereof an exposed comparatively thinflexible Wax film coating completely covering said surface and therebyimparting moistureproof properties theretd and on its other surface anexposed exible dried wax-free film consisting essentially of a rubber inan unvulcanized state, said last mentioned film covering the completesaid other surface of the sheet and being substantiallyv dry andnon-tacky and yieldingly selfadhering when portions thereof are broughtinto engagement, but being non-adhesive to such surfaces as wood, glass,and metal, the said nontacky self-adhering lm cooperating with said waxcoating in moisture-proofing said paper sheet.

8. As a new article of manufacture, a sheet of self-sealing Wrappingpaper comprising a flexible paper base having a cohesive, substantiallydry, non-adhesive and non-tacky wax-free coating consisting essentiallyof a rubber in an unvulcanized state on the entire area of one sidethereof and marginal zones of a similar coating on its other side, saidother side of the paper base having an exposed comparatively thiniiexible film of wax over the area between said zones, said coatingsbeing exposed and adapted, when portions thereof are brought intoengagement with one another by slight -pressure during a wrappingoperation, to have such portions adhere to one another by cohesion, andserving to assist the wax lm in rendering the sheet moisture-proof.

9. As a new article of manufacture, a sheet of self-sealing wrappingpaper comprising a thin flexible calendered paper base having acohesive, substantially dry, non-adhesive and non-tacky wax-free coatingconsisting essentially of a rubber in an unvulcanizedstate on the entirearea of one side thereof and zones of a similar coating on its otherside, said other side of the paper base having an exposed exible lm ofWax over the area between said zones, said coatings being exposed andadapted, when portions thereof are brought into engagement with oneanother by slight pressure during a wrapping operation, to have suchportions adhere to one another by cohesion, and serving to assist thewax film in rendering the sheet moisture-proof.

BERTRAM L. TRILLICH.

REFERENCES CITED The following Yreferences are of record in the le ofthis patent:

Number Number 10 UNITED STATES PATENTS Name Date Ruderman Aug. 6, 1929Nollan et a1 May 24, 1938 Wilbur Sept. 26, 1939 Leslie Dec. 10, 1940Rhodes et a1 July 18, 1944 Martin Apr. 13, 1948 FOREIGN PATENTS CountryDate Great Britain Jan. 21, 1932

5. AS A NEW ARTICLE OF MANUFACTURE, A MOISTUREPROOF SHEET OFSELF-SEALING WRAPPING MATERIAL ADAPTED COMPLETELY TO ENCASE AN ARTICLEAND THEREBY SEAL THE SAME AGAINST OUTSIDE MOISTURE, SAID ARTICLECOMPRISING A THIN FLEXIBLE PAPER SHEET NORMALLY PERVIOUS TO MOISTURE,SAID SHEET HAVING ON ONE SURFACE THEREOF AN EXPOSED COMPARATIVELY THINFLEXIBLE WAX FILM COATING COMPLETELY COVERING SAID SURFACE AND THEREBYIMPARTING MOISTUREPROOF PROPERTIES THERETO AND ON ITS OTHER SURFACE ANEXPOSED FLEXIBLE DRIED WAX-FREE FILM CONSISTING ESSENTIALLY OF COALASCEDUNVULCANIZED NATURAL RUBBER PARTICLES, SAID FILM COVERING THE COMPLETESAID OTHER SURFACE OF THE SHEET AND BEING SUBSTANTIALLY DRY ANDNON-TACKY AND YIELDINGLY SELF ADHERING WHEN PORTIONS THEREOF ARE BROUGHTINTO ENGAGEMENT, BUT BEING NON-ADHESIVE TO SUCH SURFACES AS WOOD, GLASSAND METAL, THE SAID NON-TACKY SELF-ADHERING FILM COOPERATING WITH SAIDWAX COATING IN MOISTURE-PROOFING SAID PAPER SHEET.